I have the same problem upon setting up our new Workcentre 3345. I login with admin and the serial number and it asks me to change the admin password but then the Ok button remains greyed out no matter what password I choose (short, long, capitals, numbers, symbols). If I try to use a ! it says please enter a valid password which makes me think that it's not the password that's issue?
If the default 1111 or the serial number is not working you may need to reset the printer back to it's factory defaults to clear any saved passwords. Here are the instructions on how to reset the printer back to the factory defaults.
Either the password fields don't match, or the password isn't secure enough
Try something with upper and lower case, add a number and a symbol
And or try another web browser
We recently received a WorkCentre 3345 for our school. We need to login as the admin to change the fax settings and set a static IP. When we do login as the admin it immediately asks to change the password which is currently the serial number. When we enter the old password and the new password we are unable to continue. It looks like the OK is blacked out to continue. Thank you for any help we can get.